Background: Lifestyle choices are associated with cardiovascular disease and mortality. As Iran started to experience population ageing, it is important to consider and address the elderly people\\\\\\\'s needs and concerns, which might have direct impacts on their wellbeing and quality of life. Aim: There have been only a few researches into different aspects of life of the elderly population in Iran. So, this study aimed to assess the knowledge, attitude and practice (KAP) of elderly people in Tehran, Iran. Setting and design: This is a cross-sectional study that conducted in Tehran, Iran. Methods and material: Self-administered structured questionnaire was designed to measure knowledge, attitude and practice about healthy life style. The questionnaire completed by 412 elderly people during 2012. Statistical analysis used: Cronbach\\\\\\\'s alpha coefficient, Pearson correlation coefficient and analysis of variance were used in data. A higher score means better. Results: The mean score of males was significantly higher than in females. Furthermore, the average score of elderly membership in social activities was our findings revealed that the elderly have a low level of knowledge, attitude and performance towards healthy life style. Conclusion: It seems designing a comprehensive program regarding a healthy lifestyle in this population to be of prime necessity. So, our results suggest measuring the quality of life and general health status in elderly people.